The present invention relates to a device for supporting preparatory work of machine operators who extract, generate, and download various information from numerical control (NC) programs prepared for NC machining in which all machining control carried out using numerical control information, and who operate actual numerically controlled machine tools using the NC programs.
The operation of numerically controlled machine tools can be automatically controlled by inputting NC programs, and such machine tools are now widely used in many industrial fields. Computerized numerically controlled machine tools (CNC machine tools) are used in combination with microprocessing, power electronics, and software technology.
Generally, numerical control information, such as an NC program, comprises a tool selection command, a spindle speed command, a cutting speed command, a feed rate command, a spindle movement/interpolation command, miscellaneous function command, or the like, and numerical control information suitable for the machine tool which is to be the object of machining control is prepared in the form of an NC program as occasion demands.
Generally, such an NC program is prepared by an NC programmer in a programming section, or else is automatically prepared by inputting data concerning classifications of machining, areas to be machined, data of materials, shapes of parts, or the like into a device such as a CAD-CAM system, automatic programming unit, or the like. In either case, an NC programmer determines the areas to be machined based on drawings for machining which illustrate shapes of materials and shapes of parts, and then further determines machining procedures, such as tools to be used for machining the respective areas, routes of the respective tools at the time of machining, cutting conditions, and machining order. The NC program is then individually prepared or prepared by inputting data required for the automatic programming unit mentioned above. A machining operator carries out adjustment (editing for correction) of the NC program made in the manner described above by the repetition of test cutting using an actual machine tool at a machining site, and completes the NC program for machining so as to use it for machining control of the machine tool.
Further, even when the machining operator operates a machine tool using an NC program which was previously adjusted, when machining circumstances, such as machine tools or tools, differ, the operator will perform similar test cutting so as to adapt the NC program to the present machining circumstance, and will adjust the NC program as occasion demands before using it for machining control of the machine target tool. Such procedures for adjusting NC programs to be carried out by machining operators will be described with reference to the flowchart of FIG. 1 and to FIGS. 2 through 4.
Generally, a machining operator is provided with a drawing for machining as shown in FIG. 2, an NC program as shown in FIG. 3, and a tool list as shown in FIG. 4 as information for preparation of machining. In the drawing for machining of FIG. 2, only shapes and dimensions of materials, shapes and dimensions of parts, and a position of the NC program origin are illustrated. The NC program shown in FIG. 3 comprises a tool selection command, a cutting speed command, a spindle speed command, a feed rate command, a spindle movement/interpolation command, miscellaneous function commands, or the like. These commands are primitive command codes which can be interpreted and executed by a numerically controlled unit, and the primitive command codes are merely arranged in order of execution. Further, the tool list shown in FIG. 4 is made in a simple manner such that for each tool number, a shape of the tool is illustrated and a classification of the tool, the spindle speed, the cutting speed, the feed rate, and the cutting depth are specified. In a column for cutting conditions in the tool list, reference symbols N, V, F, and D represent spindle speed, cutting speed, feed rate, and cutting depth, respectively.
First, the machining operator prepares a tool illustrated in the tool list and furnishes a tool post with the tool at Step 1 shown in FIG. 1. At this time, the tool post must be furnished with a tool of dimensions such that ejection of the tool post furnished with the tool or a tool holder does not interfere with work pieces during the machining operation. For the purposes, the machining operator recognizes a number and shape of the tool to be installed based on the tool list and finds on the NC program spots where the tool number is selected. Based on the spindle movement/interpolation command instructed and shapes of materials and shapes of parts illustrated in the drawing for machining, the machining operator then recognizes the position at which an area to be machined is situated within the overall shapes of materials and parts, and determines an approximate dimension of the ejection. The tool post is then furnished with the tool so that the actual dimension of the ejection meets or exceeds the determined value.
At Step 2, a value of the NC program origin is set and stored in the numerically controlled unit so that the NC program origin is positioned as shown in the drawing for machining. Further, an offset value of the tool installed on the tool top is set and stored in the numerically controlled unit. Further, at Step 3, the NC program is input and stored in the numerically controlled unit. Here, preparatory work for no-load running which will be described hereinafter is completed.
Next, at Step 4, by executing the input NC program, the operator understands and confirms approximate machining operation to be controlled by the NC program during no-load running when no materials are installed. Further, the operator operates each block of the NC program, and precisely understands and confirms machining procedures, such as an area to be machined by each tool, a route of the tool at the time of machining the area, cutting conditions at the time of machining the area, and order of machining each area, referring to the drawing for machining. At the same time, the operator precisely understands and confirms at which locations on the NC program the tool selection command, the spindle speed command, the feed rate command, the spindle movement/interpolation command, the miscellaneous function command, and the like which execute the machining operation are issued. This comprehension and confirmation are preparation for the adjustment of the NC program to be performed while carrying out a test cutting with materials installed. The understanding and confirming work during no-load operation is repeated until the operator gains a clear understanding and confirmation as shown in Step 5. At this point, the test cutting preparation is completed.
The test cutting will be carried out in the following procedures. First, materials are installed at Step 6. At the next Step 7, in order for rapid traverse positioning to be performed at a safety speed, a traverse speed override which usually operates at the fastest speed tolerated for machine tools is regulated to 100 percent or less. Under such a condition that the rapid traverse positioning can be performed at a safety speed, the NC program is operated at Step 8 in block units. By operating the NC program in block units, the operator confirms whether or not the tool, the tool holder, the tool top, or the like interfere with the work pieces. Also, the operator confirms whether or not abnormal oscillation or noise arises during machining. Further, the operator measures the dimensions of the work pieces so as to confirm that the dimensions of the work pieces are within a tolerance, and conducts a careful examination of the surfaces of the work pieces machined so as to confirm whether or not the surfaces have desired roughness (smoothness?).
At Step 9, if the operator judges, after confirmation, that there is a problem which results from the NC program, the NC program will be revised at Step 10. At this time, the operator specifies a location such as where a spindle movement/interpolation command which may cause interference is issued, a location where a cutting condition command which may cause abnormal oscillation or noise is issued, a location where a spindle movement/interpolation command which may cause the dimensions of the work pieces to be out of a desired tolerance is issued, a location where a cutting condition command which may result in undesirable roughness of the surfaces is issued, or some other location, and then revises the specified locations. When such revision is performed, advantage is taken of the understanding and confirming work performed on the NC program during the no-load operation. The aforementioned work, such as test cutting, confirmation of the operation, and revision of the NC program is repeated until no problem arises and therefore the NC program will be suitable for a machining circumstance using the machine tool.
As described above, for the dimension of the ejection to be computed when the tool post is furnished with the tool for test cutting to be carried out by the operator and the adjustment (adjusting work) of the NC program performed during the test cutting, the operator must thoroughly understand the machining procedures, such as the overall flow of machining, each tool, and the area to be machined by the tool, a tool route, cutting conditions, or order of machining from only the limited information (NC program, drawings for machining, tool lists, or the like) provided. As described above, the machining procedures are determined when the NC programmer prepares the NC program. Thus, the machining operator learns of the machining procedures determined by the NC programmer through limited information, such as the NC program, drawings for machining, tool lists, or the like, and the machining operator must understand the machining procedures from such limited information. Further, even for an NC program once put into practical use under certain machining circumstances, such as for a specified tool or the like, the operator must perform the adjustments again when any of the machining circumstances are changed.
The present invention is made in consideration of conventional problems such as described above. An object of the present invention is to realize support for preparation of machining using the NC machine tool by extracting from machining commands on the NC program the information concerning the machining, such as tool numbers, tool routes, cutting conditions, order of machining, after the information is systematically combined, and then supplying the machining operator with the information. Further, the present invention is directed to realize further support for machining preparation by generating an area to be machined and a work piece model which is in the middle of machining after adding information concerning shapes of materials, shapes of parts, and tools, by extracting the machining area and the work piece model after systematically combining them and then by supplying the machining operator with them. Further, it is directed to provide the machining operator with an optimum fitting dimension of the tool to be used for machining or cutting conditions utilizing the information described above, automatically generate, from the NC program made by handwork, data which can be inputted into an NC program generating device, such as a CAD-CAM system, an automatic programming unit, or the like, and provide the data.
The present invention comprises machining procedure extracting means or a machining procedure extracting step which extracts machining procedures according to a machining command on an NC program in NC machining in which all machining control is carried out using the NC program; and machining procedure output means or a machining procedure outputting step which outputs the machining procedures extracted.
Further, the present invention is characterized in that the machining procedure extracting means or the machining procedure extracting step may include cutting condition extracting means or a cutting condition extracting step which combines tool numbers and cutting conditions and extracts these from an NC program, and the machining procedure outputting means or the machining procedure outputting step includes cutting condition outputting means or a cutting condition outputting step which outputs the extracted cutting conditions.
Further, the present invention may be characterized in that the machining procedure extracting means or the machining procedure extracting step further includes tool route generating means or a tool route generating step which combines and generates tool numbers and tool routes from an NC program, and the machining procedure outputting means or the machining procedure outputting step further includes tool route outputting means or a tool route outputting step which outputs the generated tool routes.
Further, the present invention is characterized in that the machining procedure extracting means or the machining procedure extracting step further includes machining type specifying means or a machining type specifying step which combines and specifies tool numbers and classifications of machining from an NC program or the NC program and classifications of tools, and the machining procedure outputting means or the machining procedure outputting step further includes machining type outputting means or a machining type outputting step which outputs the specified machining classifications.
Further, the present invention may be characterized in that the machining procedure extracting means or the machining procedure extracting step further includes machining area generating means or a machining area generating step which combines and generates tool numbers and machining areas from an NC program, shapes of tools, and shapes of materials, and the machining procedure outputting means or the machining procedure outputting step further includes machining area outputting means or a machining area outputting step which outputs the generated machining areas.
Further, the present invention may be characterized in that the machining procedure extracting means or the machining procedure extracting step may further includes work piece model generating means or a work piece model generating step which generates a work piece model at a point of exchanging tools from an NC program, shapes of tools, and shapes of materials each time tools are exchanged, and the machining procedure outputting means or the machining procedure outputting step further includes work piece model outputting means or a work piece model outputting step which outputs the generated work piece model.
Further, the present invention is characterized in that the machining procedure outputting means or the machining procedure outputting step further includes comment outputting means or a comment outputting step which inserts the machining procedures extracted into an NC program in the form of a comment.
Further, the present invention may include fitting dimension computing means or a fitting dimension computing step which computes fitting dimensions of tools to be used for machining according to a machining command on an NC program and fitting dimension outputting means or a fitting dimension outputting step which outputs the computed fitting dimensions.
Further, the present invention may also comprise optimum cutting condition computing means or an optimum cutting condition computing step which computes cutting conditions corresponding to the computed fitting dimensions and optimum cutting condition outputting means or an optimum cutting condition outputting step which outputs the computed cutting conditions.
Further, the present invention may further comprise machining type specifying means or a machining type specifying step which specifies classifications of machining from an NC program or the NC program and classifications of tools, a machining area generating means or the machining area generating step which generates machining areas from the NC program, shapes of tools, and shapes of materials, and means or a step for converting the classifications of machining specified and the machining areas generated into a format which can be inputted in an automatic programming unit.
Further, the present invention may be configured in the form of a medium in which a program to let a computer execute procedures for extracting, storing, and outputting order of machining according to a machining command on an NC program is recorded.